Volume 28, Number 2, 2004

The management and tillage change the soil structure, which in turn interferes with a series of physic-hydraulic properties in the surface soil layer. This work had as objective to evaluate chemical and physical-hydraulic soil properties that have implications on soil aggregation, macroporosity, and the available soil water in Red Latosol (Oxisol), either cropped under no-tillage or disk plowed for 20 years. The control was a native Cerrado (savannah) vegetation. Because of the absence of soils tillage and reduced machinery traffic, the […]

The understanding and quantification of the impact caused by soil use and management on the physical soil quality are fundamental for the development of sustainable agricultural systems. The objective of this research was to quantify some physical soil properties to evaluate the physical quality of a dystrophic Red Latosol (Rhodic Ferralsol) in the northwest of the State of Paraná, Brazil. Undisturbed soil samples were collected from two contiguous areas on an Experimental Farm of the State University of Maringá. One […]

Simulation models are essential instruments to understand soil organic matter dynamics and the turnover of its pools in tropical soils. The objectives of this study were: (a) simulate the effects of maize production systems under organic and mineral fertilization on soil organic matter dynamics of an Ultisol using the Century model; (b) to compare total carbon (TOC) and total nitrogen stocks (TN) and the carbon pools (C) measured in the laboratory and estimated by the Century model for the surface […]

Surface lime application has shown to be efficient for correcting soil acidity in no-tillage systems. Contrary to the expected, this effect has occurred in deeper soil layers and in a relatively short time, in spite of the low solubility of liming materials. The objectives of this research were: (a) to detect the presence of calcite and dolomite minerals originated from lime in the soil; (b) to verify chemical alterations related to soil acidity in the soil profile due to surface […]

The efficacy of no-tillage systems in reducing water erosion depends largely on the soil cover by crop residues. The study was carried out in Santa Catarina State, Southern Brazil, from August 2001 to July 2002, aiming to evaluate the decay of corn residue on the surface of an Inseptisol and its influence on soil properties. The treatments, with three replicates, were: bare soil (BS), 8.77 Mg ha-1 of air dried corn residue (CR) and 8.77 Mg ha-1 of air dried corn residue plus 100 kg ha-1 […]

The movement of trace elements in soils is closely related to factors that contribute to their retention in the solid phase, for instance adsorbed anions. In the present work, it was evaluated the effect of phosphorus (P) pre-treatment on adsorption and desorption of Cd, Cu, and Pb in A and B horizon samples of two Latosol (Oxisols): a Yellow-Red Latosol and a Dark-Red Latosol. The P pre-treatment consisted of reacting soils samples for 72 h with 10.75 mmol L-1 Ca(H2PO4)2.H2 O (soil:solution […]

Sewage sludge from wastewater treatments contains organic matter and plant nutrients that may play an important role in agricultural production and maintenance of soil fertility. The present study aimed to evaluate the effect of increasing sewage sludge rates on soil chemical properties, heavy metal concentration in soils and plants, and the growth of maize and bean plants cultivated in pots under greenhouse conditions. Two soil types with different clay contents were used for application of six sewage sludge rates (equivalent […]

The vegetation cover plays a key role in protection and conservation of natural resources, particularly concerning soils. This study had as objective to analyze space and time dimensions of anthropic influence on the vegetation cover in part of the semi-arid region of the Ceará State, Brazil. LANDSAT TM-5 satellite images of 1985 and 1994 combined with geoprocessing techniques were used to verify the hypothesis of intensification of environmental degradation. Maps of the vegetation cover, land use, soils, and hydrography were […]

This work aimed to evaluate the effects of sewage sludge application on the saturated and unsaturated hydraulic conductivity of a eutrophyc Red Latosol (Oxisol) during two consecutive years. This field experiment was conducted in a complete randomized block design with 3 replications and with the following treatments: control and increasing doses organic fertilization with sewage sludge (6, 12, 18, 24, and 36 Mg ha-1 on a dry basis) and mineral supplementation. The conductivity was measured in the field with a controlled suction […]